A method to repair a component of a space vehicle during orbit is needed, as evidenced by the tragic loss of the Columbia space shuttle. Particularly critical is the need for a method and material for repairing a component in the form of, for example, a leading portion of a wing or other control surface, or other leading portion of the space vehicle, which is designed and initially fabricated to experience and withstand extreme heat and an associated oxidation environment due to frictional contact with the Earth's atmosphere during high speed reentry of the space vehicle from orbit or other travel in outer space. As used herein, the term “space vehicle” refers to a manned or unmanned vehicle that is capable of traveling in outer space and reentering the Earth's atmosphere including, but not limited to, a space shuttle, a rocket, or a suitably configured satellite. However, repairing the component while the space vehicle remains in orbit poses unique challenges due to the vacuum and microgravity environment of space.
Ceramic adhesives are known in the art to bond two or more ceramic materials to one another. U.S. Pat. No. 6,692,597 to Mako et al. discloses a method of joining silicon carbide (“SiC”) materials using a slurry of allylhydridopolycarbosilane (“AHPCS”) and a multimodal SiC powder. The slurry is applied to each of the SiC materials and is heated to pyrolyze the AHPCS, forming a transition layer that bonds the SiC materials. U.S. Pat. No. 5,922,628 to Barton et al. discloses a method of joining ceramic and ceramic composite materials at a low temperature using a three-component, bonding agent. The bonding agent includes a preceramic polymer, an aluminum powder, and a boron powder. The bonding agent is applied as a layer between the ceramic materials and is heated to pyrolyze the preceramic polymer, bonding the ceramic materials. The bonding agent is also used to repair cracks, pinholes, or depressions in the ceramic and ceramic composite materials.
U.S. Pat. No. 5,582,861 to Schwab et al. discloses a method of repairing damage to an oxidation-resistant layer on a carbon/carbon composite. The oxidation-resistant layer is a layer of SiC or silicon nitride, which is applied to the carbon/carbon composite to prevent oxidation of the carbon. A damaged area of the oxidation resistant layer is repaired by applying a composition that consists essentially of a polymeric thermosetting polysilazane and a ceramic powder, such as SiC or silicon nitride. The composition is then cured and fired, converting the polysilazane to a ceramic.
While ceramic adhesives are used to join or bond ceramic substrates, conventional ceramic adhesives are not currently formulated to be used in space. As a consequence, no ceramic adhesive is available for repair while in space of a damaged component of the space shuttle, or other vehicle designed for high-speed reentry from space into the atmosphere of the Earth.